This invention relates to certain imidazole derivatives, specifically, to certain 2-(imidazol-1-ylmethyl)pyridines and the corresponding quinolines. These particular compounds are able to selectively inhibit the action of the thromboxane synthetase enzyme without significantly inhibiting the action of the prostacyclin synthetase or cyclooxygenase enzymes. The compounds of the invention therefore are useful, for example, in the treatment of ischaemic heart disease, stroke, transient ischaemic attack and migraine.